Market adoption of wireless LAN (WLAN) technology has exploded, as users from a wide range of backgrounds and vertical industries have brought this technology into their homes, offices, and increasingly into the public air space. This inflection point has highlighted not only the limitations of earlier-generation systems, but also the changing role that WLAN technology now plays in people's work and lifestyles across the globe. Indeed, WLANs are rapidly changing from convenience networks to business-critical networks. Increasingly users are depending on WLANs to improve the timeliness and productivity of their communications and applications, and in doing so, require greater visibility, security, management, and performance from their network.
Certain wireless network protocols assume that wireless clients are constantly able to listen to network signals. This is true even for protocols that support so-called “sleep or power save” modes in which the wireless client spends part of its time with its power switched off or set to a very low level and then “wakes up” to listen for network signals and to keep a network informed of its presence. When the wireless client roams, the wireless client needs to acquire knowledge of the locally available access points, which can be time consuming and energy inefficient, especially in networks that have not been designed to support efficient roaming. The problem is worsened by the fact that the combination of roaming and planned coverage in only specific areas (e.g., hotspots) render the presence of a given service provider at a given location highly unpredictable. Therefore, a wireless client has to expend time and energy in network monitoring and acquisition. This leads to battery depletion, and thus to a bad user experience.